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 rf choke for 10m use 
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Post rf choke for 10m use
In trying to find out the strange happenings with a 10m vertical i have found rf in the shack.
What would be the most effective choke for 10m?
Thanks.

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Sun Feb 26, 2012 11:13 am
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
see here http://www.karinya.net/g3txq/chokes/

MM0WAX

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Brian
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Sun Feb 26, 2012 11:27 am
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
Hello, thanks for the link, i was actually looking at that earlier on today ,i still don't know which would be best option for me though :scratch: .

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Sun Feb 26, 2012 12:14 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
In order of effectiveness:

8 turns of RG58 on a FT240-61 core
8 turns of RG58 on a FT240-31 core
8 turns of RG58 on a FT240-43 core
4 turns of RG58 on 4.25" diameter PVC pipe

73,
Steve G3TXQ


Sun Feb 26, 2012 12:43 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
Thanks for the reply Steve i have tried 4 turns of RG8 on 4.25" diameter PVC pipe which as helped a little but not cured it , i'm going to try 8 turns of RG58 on a FT240-61 core ,where would be the best place for it ? at the antenna base or further away.

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Sun Feb 26, 2012 12:59 pm
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 rf choke for 10m use 
Silent Key

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Post Re: rf choke for 10m use
Usually right at the base of the antenna. But what sort of vertical is it? And what ground system are you using?

73,
Steve G3TXQ


Sun Feb 26, 2012 1:05 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
It the thunderpole 5 i'm having trouble with on the other thread Steve , its an end fed 1/2 wave cb antenna.
looks like its the stray rf thats causing the issue i'm having with swr ,looks like the atu is activating while turned off hence the swr flickering and shooting down , i have read this morning while looking at chokes someone else with the same issue.

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Sun Feb 26, 2012 1:18 pm
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 rf choke for 10m use 
Silent Key

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Post Re: rf choke for 10m use
I'm not familiar with the antenna but it looks like yet another end fed half-wave; in that case it probably needs at least some unchoked length of feedline to act as the "counterpoise".

I would try a really good choke - the FT240-61 one - just before the feedpoint; if you can't get a satisfactory SWR with the choke there, try moving it back 8ft from the feedpoint or right back at the radio.

Steve G3TXQ

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Sun Feb 26, 2012 4:09 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
Thanks for the info Steve ,i did put the air wound choke 8 foot down ,'ll get hold of a FT240-61 and give it a go.
Just ordered the ferrite so hopefully i'll get this sorted next week.

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Sun Feb 26, 2012 4:57 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
Steve is there any particular method of winding the coax or doesn't matter as long as its 8 turns.
Thanks.

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Mon Feb 27, 2012 6:37 pm
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 rf choke for 10m use 
Silent Key

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Post Re: rf choke for 10m use
Nothing special! Just evenly space them around the core; or, if it helps mechanically to have input and output at opposite ends, do a "cross over about half-way round. Here's a bifilar wound choke that shows the "cross over" arrangement.
Image

By the way, that example has 8 turns on it.

73,
Steve G3TXQ


Mon Feb 27, 2012 7:28 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
Thanks Steve :good:

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Mon Feb 27, 2012 7:45 pm
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 rf choke for 10m use 
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Post Re: rf choke for 10m use
Choke now fitted although its helped its still giving a little rf .

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Tue Feb 28, 2012 7:23 pm
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